U.S. patent application number 16/616638 was filed with the patent office on 2020-04-09 for use of a clean composition for 3d-printed articles and related process.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Adrian S. Eckert, Anja Friedrich, Michael Jahns, Malte Korten, Gioacchino Raia, Gallus Schechner, Arno Schmalzl.
Application Number | 20200109357 16/616638 |
Document ID | / |
Family ID | 59021249 |
Filed Date | 2020-04-09 |
![](/patent/app/20200109357/US20200109357A1-20200409-C00001.png)
United States Patent
Application |
20200109357 |
Kind Code |
A1 |
Jahns; Michael ; et
al. |
April 9, 2020 |
USE OF A CLEAN COMPOSITION FOR 3D-PRINTED ARTICLES AND RELATED
PROCESS
Abstract
The invention relates to the use of a cleaning composition for
removing uncured printing resin from 3D-printed articles, the
cleaning composition comprising either of the following components
alone or in combination: di basic esters of a carboxylic acid, tri
basic esters of a carboxylic acid. The invention also relates to a
process of cleaning a 3D-printed article, the process comprising
the steps of a) providing the cleaning composition and a 3D-printed
article comprising uncured printing resin on its surface, b)
treating the surface of the 3D-printed article with the cleaning
composition, c) optionally treating the 3D article with a solvent,
in particular water, d) optionally drying the 3D article,
optionally repeating steps b), c) and d) either singly or in
combination. A further embodiment of the invention is directed to
kit of parts comprising the cleaning composition and a 3D-printable
resin composition, as well as a 3D-printing system comprising the
cleaning composition, a 3D-printing device and a 3D-printable resin
composition.
Inventors: |
Jahns; Michael; (Gilching,
DE) ; Friedrich; Anja; (Munchen, DE) ; Korten;
Malte; (Moorenweis, DE) ; Raia; Gioacchino;
(Turkenfeld, DE) ; Eckert; Adrian S.; (Herrsching,
DE) ; Schechner; Gallus; (Herrsching, DE) ;
Schmalzl; Arno; (Woerthsee, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
59021249 |
Appl. No.: |
16/616638 |
Filed: |
May 17, 2018 |
PCT Filed: |
May 17, 2018 |
PCT NO: |
PCT/US2018/033073 |
371 Date: |
November 25, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C11D 7/266 20130101;
B08B 3/102 20130101; B08B 3/12 20130101; B08B 2220/04 20130101;
B33Y 40/00 20141201; B29C 64/35 20170801; B33Y 40/20 20200101; C11D
11/0035 20130101; B08B 2203/007 20130101; B08B 3/08 20130101; C11D
7/5022 20130101 |
International
Class: |
C11D 7/26 20060101
C11D007/26; C11D 11/00 20060101 C11D011/00; B29C 64/35 20060101
B29C064/35; B33Y 40/20 20060101 B33Y040/20; B08B 3/08 20060101
B08B003/08; B08B 3/10 20060101 B08B003/10; B08B 3/12 20060101
B08B003/12 |
Foreign Application Data
Date |
Code |
Application Number |
May 29, 2017 |
EP |
17173184.7 |
Claims
1. Use of a cleaning composition for removing uncured printing
resin from a 3D-printed article, the cleaning composition
comprising either of the following components alone or in
combination: di basic esters of a carboxylic acid; tri basic esters
of a carboxylic acid.
2. The use according to claim 1, the 3D-printed article comprising
cured (meth)acrylate components and optionally fillers.
3. The use according to claim 1, the cleaning composition being
characterized by at least one of the following features alone or in
combination: having a pH value from 6 to 8, if brought in contact
with wet pH sensitive paper; being miscible with water up to a
ratio of 1 (composition):2 (water) by weight.
4. The use according to claim 1, the esters of carboxylic acid
contained in the cleaning composition being characterized by at
least one of the following features alone or in combination: having
a boiling point above 150.degree. C. (at 1013 hPa); having a vapor
pressure below 2 hPa at 25.degree. C.; having a molecular weight in
the range of 100 to 600 g/mol; having a flash point above
30.degree. C.
5. The use according to claim 1, the esters of carboxylic acid
being characterized by the following features: comprising a
saturated or unsaturated, branched or linear C.sub.1 to C.sub.12
backbone, comprising two or three carboxylic acid ester moieties
attached to the backbone, wherein the ester moieties are selected
from C.sub.1 to C.sub.4 alkyl esters.
6. The use according to claim 1, the esters of carboxylic acid
being selected from methyl and ethyl esters of malonic acid,
succinic acid, glutaric acid, adipic acid, citric acid and mixtures
thereof.
7. The use according to claim 1, comprising in addition either of
the following components alone or in combination: solvent(s) having
a boiling point above 100.degree. C., solvent(s) having a vapor
pressure below 2 hPa at 25.degree. C.
8. The use according to claim 7, the cleaning composition
comprising: ester(s) of carboxylic acid in an amount of 25 to 99.9
wt. %, solvent(s) having a boiling point above 100.degree. C. in an
amount of 0.1 to 75 wt. %, wt. % with respect to the weight of the
whole composition.
9. The use according to claim 7, the cleaning composition
comprising: a di-basic ester of a carboxylic acid in an amount of
25 to 100 wt. %, a tri-basic ester of a carboxylic acid in an
amount of 1 to 25 wt. %, solvent(s) having a boiling point above
100.degree. C. in an amount of 1 to 75 wt. %, wt. % with respect to
the weight of the whole composition.
10. A process for removing uncured printing resin from a 3D-printed
article, the process comprising: providing the cleaning composition
of claim 1 and a 3D-printed article comprising uncured printing
resin on its surface, treating the surface of the 3D-printed
article with the cleaning composition, optionally treating the
3D-printed article with a solvent, in particular water, optionally
drying the 3D-printed article, optionally repeating the above steps
either singly or in combination.
11. The process according to claim 10, the treating step being
conducted for a period of 1 to 40 min, optionally by applying
ultrasound, stirring and/or agitation.
12. The process according to claim 10, the treating step b) being
conducted within a temperature range of 20 to 200.degree. C.
13. The process according to claim 10, the 3D-printed article
having the shape of a dental article or orthodontic article.
14. A kit of parts comprising: the cleaning composition of claim 1;
and a 3D-printable resin composition comprising radiation curable
components, preferably (meth)acrylate components.
15. A 3D-printing system comprising: the cleaning composition of
claim 1; a 3D-printing device; and a 3D-printable resin composition
comprising radiation curable components, preferably (meth)acrylate
components.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a cleaning composition for cleaning
3D-printed articles, in particular for 3D-printed articles
comprising radiation cured polymers such as cured (meth)acrylate
components.
[0002] The cleaning composition is in particular useful for
removing uncured printing resin from freshly 3D-printed parts made
by stereolithography (SLA), such as 3D-printed articles for use in
the dental or orthodontic field.
BACKGROUND ART
[0003] The SLA production of 3D-articles involves the layer-wise
radiation curing of radiation-curable compositions.
[0004] Further, after the radiation curing process is finished, the
3D-printed article has to be removed from the printing vat with the
result that on the surface of the obtained 3D-printed article
uncured printing resin is present. The uncured resin has to be
removed afterwards.
[0005] Currently, this cleaning procedure is keeping 3D-printing
from being a simple and clean manufacturing procedure, in
particular in the dental and orthodontic area.
[0006] The current state-of-the-art for cleaning 3D-printed (SLA)
parts typically involves the use of iso-propanol with repeated
ultrasonic treatment and rinsing.
[0007] This method is rather time consuming and, without a fume
hood, user and environment are exposed to flammable, organic
vapours. Alternative approaches are described in the following
documents:
[0008] U.S. Pat. No. 5,482,659 (Sauerhofer) describes a method of
evacuating uncured resin from internal passages of semi-hollow SLA
produced objects. As cleaning solution iso-propanol is
suggested.
[0009] WO2015070165 A1 (Mosher et al.) relates to a method for
removing the support structure from a 3D-printed object using an
electrolytic solution.
[0010] JP 2011/00566 describes an apparatus for removing a support
material from a modelled object formed by a 3D printer using a
certain treatment solution. The treatment solution is composed of
silicate, phosphate and water.
[0011] DE 10 2009 061 069 A1 (Schulz) describes a rinsing
composition for removing supporting material from 3D-printed
articles. The rinsing composition is an aqueous solution containing
5-15% non-ionic tensides, 5-10% glycol, and up to 5% sodium
hydroxide.
[0012] The commercially available product Anmasi.TM. SLA-Cleaner
2000 contains approx. 0-50% water and 50-100% di(ethylene glycol)
monobutyl ether, which is a carbitol.
SUMMARY OF INVENTION
[0013] None of the solutions described in the art is completely
satisfying. There is still a need for a cleaning composition for
cleaning 3D-printed articles which allows a time efficient removal
of uncured printing resin from the 3D-printed article, in
particular 3D-printed articles obtained by radiation curing a
light-curable composition comprising (meth)acrylate component(s)
and filler(s).
[0014] The cleaning composition should be easy to use and suitable
for cleaning in particular small objects like dental and
orthodontic articles produced by the dental technician in a
so-called chair-side 3D-printing process. Further, the cleaning
composition should be non-hazardous.
[0015] Ideally, the cleaning composition should also be suitable
for conducting a post-curing step of the 3D-printed article, if
desired.
[0016] This object is achieved by the cleaning composition and kit
of parts and related processes described in the present text and
claims.
[0017] In one embodiment the invention features the use of a
cleaning composition for cleaning 3D-printed articles, the cleaning
composition comprising either of the following components alone or
in combination: di basic esters of a carboxylic acid, tri basic
esters of a carboxylic acid.
[0018] Alternatively, the cleaning composition is characterized as
comprising ester(s) of carboxylic acids having a vapour pressure
below 2 hPa at 25.degree. C.
[0019] In another embodiment, the invention relates to a process of
cleaning a 3D-printed article, the process comprising the steps
of:
[0020] a) providing the cleaning composition as described in any of
the preceding claims and a 3D-printed article,
[0021] b) treating the surface of the 3D-printed article with the
cleaning composition,
[0022] c) optionally treating the 3D article with a solvent, in
particular water,
[0023] d) optionally drying the 3D article,
optionally repeating steps b), c) and d) either singly or in
combination.
[0024] A further embodiment of the invention is directed to kit of
parts comprising the cleaning composition described in the present
text and a 3D-printable resin composition.
[0025] The invention is also related to a 3D-printing system
comprising the cleaning composition described in the present text,
a 3D printing device, and a 3D-printable resin composition
comprising (meth)acrylate components.
[0026] "Additive manufacturing" or "3d printing" means processes
comprising a layer-wise creation of an object from digital data.
The articles can be of almost any shape or geometry and are
produced from a 3-dimensional model or other electronic data
source.
[0027] Many 3D printing technologies exist, one of them being vat
polymerization which uses a radiation curing step to make
3-dimensional articles.
[0028] Examples of vat polymerization techniques include
stereolithography (SLA) and digital light processing (DLP) in which
successive layers of material are cured by a laser (SLA) and a
projector (DLP).
[0029] In the present text the term "stereolithographic" and the
respective abbreviation SLA are used for all sorts of vat
polymerization techniques.
[0030] A "hardenable component or material" or "polymerizable
component" is any component which can be cured or solidified in the
presence of a photo initiator by radiation-induced polymerization.
A hardenable component may contain one, two, three or more
polymerizable groups. Typical examples of polymerizable groups
include unsaturated carbon groups, such as a vinyl group being
present i.a. in a (methyl)acrylate group.
[0031] A "monomer" is any chemical substance which can be
characterized by a chemical formula, bearing polymerizable groups
(including (meth)acrylate groups) which can be polymerized to
oligomers or polymers thereby increasing the molecular weight. The
molecular weight of monomers can usually simply be calculated based
on the chemical formula given.
[0032] As used herein, "(meth)acryl" is a shorthand term referring
to "acryl" and/or "methacryl". For example, a "(meth) acryloxy"
group is a shorthand term referring to either an acryloxy group (i.
e., CH.sub.2.dbd.CH--C(O)--O--) and/or a methacryloxy group (i. e.,
CH.sub.2.dbd.C(CH.sub.3)--C(O)--O--).
[0033] A "curing, hardening or setting reaction" is used
interchangeable and refers to a reaction, wherein physical
properties such as viscosity and hardness of a composition changes
over the time due to a chemical reaction between the individual
components.
[0034] A "photo initiator" is a substance being able to start or
initiate the curing process of a hardenable composition in the
presence of radiation, in particular light (wave length from 300 to
700 nm).
[0035] The term "dental or orthodontic article" means any article
which is to be used in the dental or orthodontic field, especially
for producing a dental restoration, orthodontic devices, a tooth
model and parts thereof.
[0036] Examples of dental articles include crowns, bridges, inlays,
onlays, veneers, facings, copings, crown and bridged framework,
implants, abutments, dental milling blocks, monolithic dental
restorations and parts thereof.
[0037] Examples of orthodontic articles include brackets, buccal
tubes, cleats and buttons and parts thereof.
[0038] A dental or orthodontic article should not contain
components which are detrimental to the patient's health and thus
free of hazardous and toxic components being able to migrate out of
the dental or orthodontic article.
[0039] "Ambient conditions" mean the conditions which the
composition described in the present text is usually subjected to
during storage and handling. Ambient conditions may, for example,
be a pressure of 900 to 1100 hPa, a temperature of 10 to 40.degree.
C. and a relative humidity of 10 to 100%. In the laboratory ambient
conditions are typically adjusted to 20 to 25.degree. C. and 1000
to 1025 hPa.
[0040] A composition is "essentially or substantially free of" a
certain component, if the composition does not contain said
component as an essential feature. Thus, said component is not
willfully added to the composition either as such or in combination
with other components or ingredient of other components. A
composition being essentially free of a certain component usually
does not contain that component at all. However, sometimes the
presence of a small amount of the said component is not avoidable
e.g. due to impurities contained in the raw materials used.
[0041] As used herein, "a", "an", "the", "at least one" and "one or
more" are used interchangeably. The terms "comprise" or "contain"
and variations thereof do not have a limiting meaning where these
terms appear in the description and claims. Also herein, the
recitations of numerical ranges by endpoints include all numbers
subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75,
3, 3.80, 4, 5, etc.).
[0042] Adding an "(s)" to a term means that the term should include
the singular and plural form. E.g. the term "additive(s)" means one
additive and more additives (e.g. 2, 3, 4, etc.).
[0043] Unless otherwise indicated, all numbers expressing
quantities of ingredients, measurement of physical properties such
as described below and so forth used in the specification and
claims are to be understood as being modified in all instances by
the term "about". The term "comprise" shall include also the terms
"consist essentially of" and "consists of".
DETAILED DESCRIPTION
[0044] This cleaning composition described in the present text
helps to improve the cleaning of 3D-printed articles in particular
those obtained by SLA.
[0045] The proposed cleaning composition is suitable to simplify
and accelerate the cleaning procedure of 3D-printed articles.
[0046] It was found that good cleaning results can be achieved, if
components are used which are chemically similar to the monomers
contained in the printing resin used in the SLA process.
[0047] The components used in the cleaning composition described in
the present text are non-hazardous substances.
[0048] Further, due to their relatively high molecular weight, the
components typically have a high boiling point and low vapour
pressures. This may enable the use of the cleaning composition even
without a fume hood.
[0049] It was found that due to a lower vapour pressure, the
diesters of carboxylic acids are better suited than the monoesters
of carboxylic acids, in particular for cleaning processes conducted
between room temperature and 80.degree. C.
[0050] Sometimes, it can be desirable to conduct in parallel a
thermal post-curing step. Such a thermal treatment typically
involves temperatures of 80.degree. C. and above.
[0051] The cleaning composition described in the present text is
also suitable for conducting such a thermal post-curing step.
[0052] For this purpose, triesters of carboxylic acids are
suggested as they possess even higher molecular weights and boiling
points.
[0053] However, due to the higher viscosity of triesters at room
temperature, their full cleaning potential is typically achieved at
elevated temperatures anyway.
[0054] As mentioned above, the components of the cleaning
composition described in the present text have a low vapour
pressure. Thus, they do not evaporate from the surface of the
3D-printed article after the cleaning step.
[0055] Thus, a rinsing step is typically needed to finally remove
the cleaning composition from the surface of the 3D-printed
article. This can be done with water. Esters are sometimes not
fully miscible with water.
[0056] If a better miscibility with water is needed or desired, the
esters can be mixed with polar solvents having a high boiling
point.
[0057] The use of carbitols was found to be particular useful in
this respect. Carbitols are readily miscible with water and also
with esters, working as a moderator between them.
[0058] At the same time, carbitols, like the esters, have high
boiling points and usually are non-hazardous substances.
[0059] The cleaning composition described in the present text is in
particular useful for cleaning 3D-printed articles which were
produced by processing a filled radiation-curable printing
composition in a stereolithographic 3D-printing process.
[0060] Filled radiation-curable printing compositions include
printing compositions containing (meth)acrylate component(s) and
filler(s) in an amount of at least 20 or at least 30 or at least 40
wt. % with respect to the weight of the printing composition.
[0061] The cleaning composition is in particular useful for
cleaning 3d-printed articles having small dimensions and/or a
surface geometry with concave and convex structures and optionally
undercuts, like dental articles or orthodontic articles as
described above.
[0062] The cleaning composition described in the present text
contains di basic esters of carboxylic acids, tri basic esters of
carboxylic acids or a mixture thereof.
[0063] The cleaning composition is for cleaning 3D-printed
articles, in particular for 3D-printed articles obtained by
radiation curing of (meth)acrylate components containing radiation
curable compositions.
[0064] The cleaning composition described in the present text can
typically be characterized by the following features alone or in
combination: [0065] having a pH value from 6 to 8 if brought in
contact with wet pH sensitive paper; [0066] being miscible with
water up to an amount of 2 parts by weight of water with respect to
1 part by weight of cleaning composition. That is, the pH of the
cleaning composition is typically in the neutral range.
[0067] Further, the cleaning composition is typically not
completely soluble in and miscible with water. The cleaning
composition is provided as a one-phase system.
[0068] The cleaning composition described in the present text
comprises carboxylic acid ester(s).
[0069] The carboxylic acid ester(s) can typically be described by
the following features alone or in combination:
[0070] having a boiling point above 150.degree. C. at 1013 hPa;
[0071] having a vapour pressure below 2 hPa at 25.degree. C.;
[0072] having a molecular weight in the range of 90 to 1,000 g/mol
or 100 to 600 g/mol;
[0073] having a flash point above 30.degree. C. or above 50.degree.
C.
[0074] According to one embodiment, suitable di and tri basic
carboxylic acid esters are characterized by the following features:
[0075] comprising a saturated or unsaturated, branched or linear
C.sub.1 to C.sub.12 backbone, [0076] comprising two or three
carboxylic acid ester moieties attached to the backbone, [0077]
wherein the ester moieties are selected from C.sub.1 to C.sub.4
alkyl esters.
[0078] The di-basic carboxylic acids of the carboxylic acid esters
used in the cleaning composition described in the present text are
typically selected from acids characterized by the following
formula:
(HOOC)--(CH.sub.2).sub.n--(COOH),
with n being selected from 1 to 12.
[0079] In particular, the following di-basic carboxylic acids were
found to be useful: propanedionic acid, butanedionic acid,
pentanedionic acid, hexandionic acid, heptanedionic acid,
octanedioic acid, nonanedionic acid, decanedionic acid and mixtures
thereof.
[0080] The tri-basic carboxylic acids of the carboxylic acid esters
used in the cleaning composition described in the present text are
typically selected from citric acid, iso-citric acid, aconitic
acid, trimesic acid, propane-1,2,3-tricarboxylic acid and mixtures
thereof.
[0081] The alcohols of the carboxylic acid esters used in the
cleaning composition described in the present text are typically
selected from C.sub.1 to C.sub.4 alcohol and mixtures thereof, in
particular methanol, ethanol, n-propanol, n-butanol, iso-butanol
and mixtures thereof.
[0082] Suitable examples of carboxylic acid esters include the
methyl and ethyl esters of malonic acid, succinic acid, glutaric
acid, adipic acid, citric acid and mixtures thereof.
[0083] Using a mixture of di and tri basic carboxylic acid esters
can be preferred, to adjust the cleaning properties.
[0084] If the cleaning composition comprises a mixture of di and
tribasic carboxylic acid esters, the following ration was found to
be useful: di basic carboxylic acid ester/tri basic carboxylic acid
ester: from 3/1 to 1/3 with respect to weight or from 2/1 to
1/2.
[0085] According to one embodiment, the cleaning composition
described in the present text comprises the carboxylic acid esters
typically in the following amounts: Di basic ester of carboxylic
acid: 20 to 100 wt. % or 30 to 100 wt. %, Tri basic ester of
carboxylic acid: 0 to 80 wt. % or 0 to 70 wt. %, wt. % with respect
to the weight of the whole composition.
[0086] The cleaning composition described in the present text may
also comprise additive(s).
[0087] Suitable additive(s) include solvent(s), in particular
solvent(s) having a high boiling point, e.g. a boiling point above
100.degree. C.
[0088] In certain embodiments the high boiling additive(s) or
solvent(s) can be characterized by at least one or more, sometimes
all of the following parameters: [0089] Boiling point: above 100 or
above 200 or above 250 or above 300.degree. C.; [0090] Vapour
pressure: below 2 hPa or below 1 hPa at 25.degree. C.; [0091]
Molecular weight: 100 to 1000 g/mol or 150 to 800 g/mol or 200 to
600 g/mol; [0092] Flash point above 30.degree. C. or above
50.degree. C.
[0093] Using a high boiling additive with a boiling point above 100
or above 200 or above 250 or above 300.degree. C. can be beneficial
as it may help to improve the post-curing thermal treatment
capability of the cleaning composition.
[0094] The high boiling solvent is typically a high boiling polar
solvent, that is, a high boiling solvent being miscible with water
without phase separation.
[0095] According to one embodiment, the high boiling solvent is
often an alcohol or a glycol or polyglycol, mono-ether glycol or
mono-ether polyglycol, di-ether glycol or di-ether polyglycol,
ether ester glycol or ether ester polyglycol, carbonate, ester or a
polycaprolactone. The organic high boiling point additives usually
have one or more polar groups. The organic high boiling point
additive does not have a polymerizable group; that is, the organic
high boiling point additive is free of a group that can undergo
free radical polymerization. Further, no component of the high
boiling point additive medium has a polymerizable group that can
undergo free radical polymerization.
[0096] Suitable glycols or polyglycols, mono-ether glycols or
mono-ether polyglycols, di-ether glycols or di-ether polyglycols,
and ether ester glycols or ether ester polyglycols are often of the
following formula:
R.sup.1O--(R.sup.2O).sub.n--R.sup.1
In the above formula each R.sup.1 independently is hydrogen, alkyl,
aryl, or acyl. Suitable alkyl groups often have 1 to 10 carbon
atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Suitable aryl
groups often have 6 to 10 carbon atoms and are often phenyl or
phenyl substituted with an alkyl group having 1 to 4 carbon atoms.
Suitable acyl groups are often of formula --(CO)R.sup.a where
R.sup.a is an alkyl having 1 to 10 carbon atoms, 1 to 6 carbon
atoms, 1 to 4 carbon atoms, 2 carbon atoms, or 1 carbon atom. The
acyl is often an acetyl group (i.e. --C(O)CH.sub.3). In the above
formula, each R.sup.2 is typically an alkylene group such as
ethylene or propylene. The variable n is at least 1 and can be in a
range of 1 to 10, 1 to 6, 1 to 4, or 1 to 3.
[0097] Glycols or polyglycols of the above formula have two R.sup.1
groups equal to hydrogen. Examples of glycols include, but are not
limited to, ethylene glycol, propylene glycol, diethylene glycol,
dipropylene glycol, triethylene glycol, and tripropylene
glycol.
[0098] Mono-ether glycols or mono-ether polyglycols of the above
formula have a first R.sup.1 group equal to hydrogen and a second
R.sup.1 group equal to alkyl or aryl. Examples of mono-ether
glycols or mono-ether polyglycols include, but are not limited to,
ethylene glycol monohexyl ether, ethylene glycol monophenyl ether,
propylene glycol monobutyl ether, diethylene glycol monomethyl
ether, diethylene glycol monoethyl ether, diethylene glycol
monopropyl ether, diethylene glycol monobutyl ether, diethylene
glycol monohexyl ether, dipropylene glycol monomethyl ether,
dipropylene glycol monoethyl ether, dipropylene glycol monopropyl
ether, triethylene glycol monomethyl ether, triethylene glycol
monoethyl ether, triethylene glycol monobutyl ether, tripropylene
glycol monomethyl ether, and tripropylene glycol monobutyl
ether.
[0099] Di-ether glycols or di-ether polyglycols of the above
formula have two R1 group equal to alkyl or aryl. Examples of
di-ether glycols or di-ether polyglycols include, but are not
limited to, ethylene glycol dipropyl ether, ethylene glycol dibutyl
ether, dipropylene glycol dibutyl ether, diethylene glycol dimethyl
ether, diethylene glycol diethyl ether, triethylene glycol dimethyl
ether, tetraethylene glycol dimethyl ether, and pentaethylene
glycol dimethyl ether.
[0100] Ether ester glycols or ether ester polyglycols of the above
formula have a first R1 group equal to an alkyl or aryl and a
second R1 group equal to an acyl. Examples of ether ester glycols
or ether ester polyglycols include, but are not limited to,
ethylene glycol butyl ether acetate, diethylene glycol butyl ether
acetate, and diethylene glycol ethyl ether acetate.
[0101] Other suitable organic high boiling additives are carbonates
of the following formula:
##STR00001##
In the above formula, R.sup.3 is hydrogen or an alkyl such as an
alkyl having 1 to 4 carbon atoms, 1 to 3 carbon atoms, or 1 carbon
atom. Examples include ethylene carbonate and propylene
carbonate.
[0102] Suitable are also polycaprolactones, in particular
polycaprolactones having a molecular mass in the range of 200 to
1,000 or from 300 to 800 or 400 to 600 g/mol.
[0103] Polycaprolactones are typically the reaction products of
caprolactone with diols or triols. Typical examples of diols
include ethylene glycol, propylene glycol, butanediol, hexanediol,
diethylene glycol. A typical example of a triol includes
trimethylolpropane.
[0104] Specific examples of high boiling point additives which can
be used include: mono alcohols (e.g. C.sub.6 to C.sub.12 alcohols,
including primary, secondary and tertiary alcohols), poly alcohols
(e.g. diethylene glycol ethyl ether (Carbitol.TM.), hexanediol,
octanediol, decanediol, dodecanediol), and mixtures thereof.
[0105] The following high boiling additives are sometimes
preferred: polyethylene glycol, polycaprolactone, diethylene glycol
ethyl ether, propylene carbonate and mixtures thereof.
[0106] If present the high boiling solvent is typically present in
the following amounts: [0107] Lower limit: at least 10 or at least
20 or at least 30 wt. %; [0108] Upper limit: at most 80 or at most
75 or at most 70 wt. %; [0109] Range: 10 to 80 or 20 to 75 or 30 to
70 wt. %; wt. % with respect to the weight of the whole
composition.
[0110] Other additive(s) which can be added are colorant(s).
[0111] The addition of colorant(s) to the cleaning composition can
make it easier for the practitioner to determine if residues of the
cleaning composition are still present on the surface of the
treated 3D-printed article or not.
[0112] Suitable colorant(s) include organic colorant(s) like food
colorants, e.g. Acid Red 18 (E124) or Acid Green 50 (E142) or
Beetroot Red (E162) and colorants for non-food applications, e.g.
Macrolex.TM. Violet B or Solvaperm.TM. Red PFS and mixtures
thereof.
[0113] According to one embodiment, the cleaning composition
comprises:
[0114] a di-basic carboxylic acid ester in an amount of 30 to 90
wt. %,
[0115] a tri-basic carboxylic acid in an amount of 10 to 40 wt.
%,
[0116] glycol ether, such as carbitol in an amount of 0 to 40 wt.
%,
[0117] water in an amount of 0 to 10 wt. %,
wt. % with respect to the weight of the whole composition.
[0118] According to another embodiment, the cleaning composition
comprises:
[0119] a di-basic carboxylic acid ester in an amount of 10 to 50
wt. %,
[0120] a tri-basic carboxylic acid in an amount of 0 to 20 wt.
%,
[0121] glycol ether, such as carbitol in an amount of 30 to 70 wt.
%,
[0122] water of 0 to 5 wt. %,
wt. % with respect to the weight of the whole composition.
[0123] According to another embodiment, the cleaning composition
comprises:
[0124] a di-basic carboxylic acid in an amount of 0 to 40 wt.
%,
[0125] a tri-basic carboxylic acid ester in an amount of 30 to 90
wt. %,
[0126] glycol ether, such as carbitol in an amount of 0 to 40 wt.
%,
[0127] water in an amount of 0 to 10 wt. %,
wt. % with respect to the weight of the whole composition.
[0128] The cleaning composition described in the present text does
typically not contain water in an amount above 10 wt. % or above 5
wt. %.
[0129] Further, the cleaning composition described in the present
text does typically not contain non-ionic or ionic tenside(s) in an
amount above 6 wt. % or above 3 wt. %.
[0130] Further, the cleaning composition described in the present
text does typically not contain filler(s) in an amount above 1 wt.
% or above 0.1 wt. %.
[0131] Further, the cleaning composition described in the present
text does typically not contain fatty acid salts in an amount above
5 wt. % or 3 wt. % or 1 wt. %.
[0132] Unless otherwise stated, the term "wt. %" generally refers
to the weight of the whole composition.
[0133] The cleaning composition described in the present text can
be produced by simply mixing the respective components.
[0134] The cleaning composition described in the present text is
provided to the practitioner in a suitable packaging devices.
Suitable packaging devices include containers, bottles, foil bags
and cans.
[0135] The volume of the respective packaging devices is not
particularly limited, but is typically in a range of 10 to 200,000
ml or 500 to 10,000 ml.
[0136] The cleaning composition is typically not provided in form
of microcapsules or in encapsulated form.
[0137] Described is also a kit of parts comprising the cleaning
composition described in the present text and a radiation-curable
resin composition, in particular a radiation-curable resin
composition comprising (meth)acrylate components for use in an SLA
process.
[0138] Besides radiation curable components, the radiation-curable
resin composition comprises radiation-sensitive initiators, in
particular photoinitiators.
[0139] Suitable radiation-curable compositions are also
commercially available and are also described in the literature,
e.g. SHERAprint.TM.-cast or SHERAprint.TM.-model or Prodways
PLASTCure.TM. Cast 200 or Prodways PLASTCure.TM. Model 300.
[0140] The cleaning composition described in the present text is
typically provided to the practitioner with an instruction for
use.
[0141] The instruction for use typically describes under what
conditions and how the cleaning composition should and has to be
used.
[0142] The cleaning composition described in the present text is
typically used as follows:
[0143] The cleaning composition and a 3D-printed article to be
cleaned is provided.
[0144] The 3D-printed article is typically an article which has
been obtained by a stereolithographic 3D-printing process.
[0145] The 3D-printed article typically contains uncured residues
of the radiation-curable composition on its surface, which was used
for producing the 3D-printed article.
[0146] The cleaning composition described in the present text is in
particular useful for removing uncured printing resin from
3D-printed articles having convex and/or concave surface elements
optionally combined with so-called undercuts like dental and/or
orthodontic articles.
[0147] The cleaning composition described in the present text is in
particular useful for removing residues of radiation curable
compositions containing (meth)acrylate components and
filler(s).
[0148] Filler(s) which might be present include e.g. silica
particles in an amount of 5 to 30 wt. %. The silica particles are
typically surface-treated, e.g. silanized.
[0149] These kind of radiation curable compositions typically have
a viscosity in the range of 2 to 100 Pa*s (23.degree. C.) at a
shear rate of 10 s.sup.-1.
[0150] The surface of the 3D-printed article is brought in contact
and treated with the cleaning composition.
[0151] This is typically done by immersing the 3D-printed article
in the cleaning composition. If desired, ultrasound, stirring
and/or agitation can be applied.
[0152] The treatment step is typically done for a time sufficient
for removing the uncured residues. A time period of 1 to 40 min or
2 to 30 min or 2 to 20 min was found to be sufficient.
[0153] If desired, the treatment step can be done at elevated
temperature, e.g. in a temperature range above 40.degree. C. or
above 60.degree. C. but below the boiling point of the cleaning
composition.
[0154] Further, if desired, the treatment can be done by applying
ultrasound and/or stirring.
[0155] Further, the treatment can be repeated, if desired, until
the uncured residues of the radiation-curable composition is
removed.
[0156] After the treatment step, the cleaning composition remaining
on the surface of the cleaned 3D-printed article is typically
removed with a solvent, e.g. water.
[0157] The removal of the cleaning composition from the surface of
the cleaned 3D-printed article can be improved, if the cleaning
composition comprises the polar high boiling solvent(s) outlined
above, such as carbitol(s).
[0158] If desired, the surface of the cleaned 3D-printed article
can be dried afterwards.
[0159] A typical process of cleaning a 3D-printed article comprises
the following steps
[0160] a) providing the cleaning composition as described in the
present text and a 3D-printed article comprising uncured printing
resin on its surface,
[0161] b) treating the surface of the 3D-printed article with the
cleaning composition, optionally together with the application of
ultrasound, stirring and/or agitation,
[0162] c) optionally treating the surface of the 3D-printed article
with a solvent, in particular water,
[0163] d) optionally drying the 3D-printed article,
optionally repeating steps b), c) and d) either singly or in
combination
[0164] According to one embodiment, the 3D-printed article is a
dental or orthodontic article comprising cured (meth)acrylate
components and optionally filler(s).
[0165] A typical treatment procedure is as follows:
[0166] duration of treatment: 1 to 40 min or 2 to 30 min;
[0167] temperature during treatment: 20 to 200.degree. C. or 40 to
180.degree. C.;
[0168] optionally application of ultrasound.
[0169] If only high boiling components are present in the cleaning
composition that have a boiling point above e.g. 100.degree. C.,
the cleaning composition can also be used for simultaneously
conducting a post-curing thermal treatment to the 3D-printed
article.
[0170] A post-curing thermal treatment is typically conducted at
elevated temperature, e.g. above 60.degree. or 70.degree. C. or
above 80.degree., in particular in a temperature range of 60 to
200.degree. C. or 70 to 180.degree. C.
[0171] A further aspect of the invention is directed to a
3D-printing system comprising
[0172] the cleaning composition described in the present text,
[0173] a 3D-printable resin composition comprising (meth)acrylate
components,
[0174] a 3D printing device, preferably an SLA 3D-printer.
[0175] Suitable 3D printing devices are commercially available e.g.
from companies such as EnvisionTec, Rapidshape, Prodways and
Stratasys.
[0176] The complete disclosures of the patents, patent documents,
and publications cited herein are incorporated by reference in
their entirety as if each were individually incorporated. Various
modifications and alterations to this invention will become
apparent to those skilled in the art without departing from the
scope and spirit of this invention. The above specification,
examples and data provide a description of the manufacture and use
of the compositions and methods of the invention. The invention is
not limited to the embodiments disclosed herein. One skilled in the
art will appreciate that many alternative embodiments of the
invention can be made without departing from the spirit and scope
thereof.
[0177] The following examples are given to illustrate, but not
limit, the scope of this invention.
Examples
[0178] Unless otherwise indicated, all parts and percentages are on
a weight basis, all water is de-ionized water, and all molecular
weights are weight average molecular weight. Moreover, unless
otherwise indicated all experiments were conducted at ambient
conditions (23.degree. C.; 1013 hPa).
Materials
TABLE-US-00001 [0179] TABLE 1 di(ethylene glycol) ethyl ether high
boiling polar solvent; carbitol tri(propylene glycol) methyl ether
high boiling polar solvent; carbitol diethyl ester of succinic acid
dibasic carboxylic acid ester diethyl ester of glutaric acid
dibasic carboxylic acid ester diethyl ester of adipic acid dibasic
carboxylic acid ester diethyl ester of dibasic carboxylic acid
ester mixture succinic acid (10-20 wt. %) diethyl ester of glutaric
acid (55-65 wt. %) diethyl ester of adipic acid (15-25 wt. %)
triethyl ester of citric acid tribasic carboxylic acid ester light
curable composition printing resin containing (meth)acrylate
components and more than 30 wt. % filler Printing resin coloured
coloured printing resin with Macrolex .TM. Violet B and Solvaperm
.TM. Red PFS
Methods
Viscosity
[0180] If desired, the viscosity can be measured using a Physica
Rheometer MCR 301 device with a plate/cone system (diameter 25 mm
and angle 1.degree.) and a slit of 0.05 mm. The viscosity values
(Pas) can be recorded at 23.degree. C. for each shear rate
(starting from 0.1 l/s to 100 l/s in 50 exponential increasing
steps). For each shear rate, a delay of 5 s is typically used
before collecting data. Also the viscosity values can be recorded
at a constant shear of 10 l/s and an increasing temperature ramp
(starting at 23.degree. C. to 60.degree. C. in 0.74.degree. C.
steps). The above mentioned method of measurement corresponds
essentially to DIN 53018-1.
Method for Determining pH-Value
[0181] If desired, the measurement of the pH-value can be achieved
by means known by the person skilled in art. E.g. the composition
can be dispersed in de-ionized water and an instrument like
Metrohm.TM. 826 can be used. Or a wet piece of pH sensitive paper
can be brought in contact with the composition.
Method for Determining Flash Point
[0182] If desired, the flash point can be measured according to ISO
1523:2002 using the closed cup equilibrium method.
Sample Preparation and Cleaning Procedure
[0183] 3D-printed composite platelets (dimensions: 25 mm.times.15
mm.times.1 mm) were made from the printing resin described in the
materials section using a S30 3D printer from RapidShape. The
platelets were pre-cleaned by immersion in iso-propanol, which was
agitated with a magnetic stirrer unit, rinsing with de-ionized
water and drying by wiping off the water with a paper cloth.
[0184] A drop (100 mg) of coloured printing resin (printing resin
with the addition of organic colouring components) was put on a
pre-cleaned platelet to obtain a reproducible, clearly visible
contamination with printing resin.
[0185] The platelet was immersed in 40 ml of the cleaning
composition to be tested. The cleaning composition was agitated and
pre-heated with a magnetic stirrer unit.
[0186] The experimental setup allowed the agitated cleaning
composition to pass by the contaminated surface, but the platelet
was unable to move and the magnetic stir bar was not able to touch
the platelet. The time until the coloured resin was completely
removed was measured.
[0187] The experiment was performed three times in the same
cleaning composition and the cleaning times were averaged.
[0188] The colour was added to the printing resin solely to achieve
better visibility of the cleaning process. The results are given in
Table 2.
Determination of Water Miscibility:
[0189] 40 ml of solvent mixture were prepared. Water was added
dropwise under stirring, until a second phase started forming,
showing that the system was no longer miscible. The amount of water
added was recorded.
Comparative Composition #1 (C.C.1)
[0190] iso-propanol (100 wt. %)
Comparative Composition #2 (C.C.2)--Carbitol Ether
[0191] di(ethylene glycol) ethyl ether
Comparative Composition #3 (C.C.3)--Carbitol Ether
[0192] tri(propylene glycol) methyl ether
Inventive Composition #1 (I.C.1)--Dibasic Ester
[0193] mixture of diethyl esters of succinic acid, glutaric acid
and adipic acid as described in the materials section
Inventive Composition #2 (I.C.2)--Tribasic Ester
[0194] triethyl ester of citric acid
Inventive Composition #3 (I.C.3)--Dibasic Ester/Carbitol Ether
Mixture
[0195] mixture of diethyl esters of succinic acid, glutaric acid
and adipic acid as described in the materials section and
di(ethylene glycol) ethyl ether; ratio 3:1 by weight
Inventive Composition #4 (I.C.4)--Dibasic Ester/Carbitol Ether
Mixture
[0196] mixture of diethyl esters of succinic acid, glutaric acid
and adipic acid as described in the materials section and
di(ethylene glycol) ethyl ether; ratio 1:1 by weight
Inventive Composition #5 (I.C.5)--Dibasic Ester/Carbitol Ether
Mixture
[0197] mixture of diethyl esters of succinic acid, glutaric acid
and adipic acid as described in the materials section and
di(ethylene glycol) ethyl ether; ratio 1:3 by weight
Results:
TABLE-US-00002 [0198] TABLE 2 stirrer cleaning time cleaning time
setting temperature average/sec std. dev./sec C.C. 1 5 RT 3,000
n.a. C.C. 2 5 RT 650 73 C.C. 2 9 RT 259 41 C.C. 2 5 79.degree. C.
73 10 C.C. 3 5 RT 715 56 I.C. 1 5 RT 404 69 I.C. 1 9 RT 136 10 I.C.
1 5 76.degree. C. 51 6 I.C. 2 5 RT 1,800 n.a. I.C. 2 5 82.degree.
C. 82 10 I.C. 3 5 RT 454 44 I.C. 4 5 RT 491 69 I.C. 5 5 RT 562 15
C.C. = comparative composition; I.C. = inventive composition
TABLE-US-00003 water miscibility/g I.C. 3 4.8 I.C. 4 25.3 I.C. 5
46.2
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